The present invention relates to scroll type machines. More particularly, the present invention relates to scroll compressors incorporating a vapor injection system which utilizes a single large port extending through a scroll member.
Refrigeration and air conditioning systems generally include a compressor, a condenser, an expansion valve or equivalent, and an evaporator. These components are coupled in sequence in a continuous flow path. A working fluid flows through the system and alternates between a liquid phase and a vapor or gaseous phase.
A variety of compressor types have been used in refrigeration systems, including but not limited to reciprocating compressors, screw compressors and rotary compressors. Rotary compressors can both include the vane type compressors as well as the scroll machines. Scroll machines are constructed using two scroll members with each scroll member having an end plate and a spiral wrap. The spiral wraps are arranged in an opposing manner with the two spiral wraps being interfitted. The scroll members are mounted so that they may engage in relative orbiting motion with respect to each other. During this orbiting movement, the spiral wraps define a successive series of enclosed spaces, each of which progressively decreases in size as it moves inwardly from a radially outer position at a relatively low suction pressure to a central position at a relatively high pressure. The compressed gas exits from the enclosed space at the central position through a discharge passage formed through the end plate of one of the scroll members.
Refrigeration systems are now incorporating vapor injection systems where a portion of the refrigerant in gaseous form is injected into the enclosed spaces at a pressure which is intermediate the low suction pressured and the relatively high pressure or what is termed discharge pressure. This gaseous refrigerant is injected into the enclosed spaces through injection ports extending through one of the two scroll members. The injection of this gaseous refrigerant has the effect of increasing both system capacity and the efficiency of the compressor. In systems where vapor injection is incorporated to achieve maximum capacity increase, the development engineer attempts to provide a system which will maximize the amount of refrigerant gas that is injected into the enclosed pocket. By maximizing the amount of refrigerant gas that is injected, the system capacity and the efficiency of the compressor are maximized.
When developing the vapor injection system, the development engineer must ensure that the intermediate pressurized vapor that is being injected is not allowed to migrate into the suction chamber of the compressor. If the intermediate pressurized vapor does migrate into the suction area, the capacity of the compressor will actually decrease. Thus, vapor injection ports are typically placed at a location where they do not communicate with an enclosed space until the enclosed space has been sealed.
There have been attempts to locate the vapor injection ports at a position where they open just prior to the sealing of the enclosed space. The theory is that the enclosed space will be sealed prior to any of the intermediate pressurized vapor migrating to the suction chamber. While these systems have increased the amount of refrigerant vapor that is injected, the increase in the amount of refrigerant vapor that is injected is less than an optimal amount.
Thus, the continued development of vapor injection systems is directed towards increasing the amount of intermediate pressurized vapor that can be injected into the enclosed spaces.
The present invention provides the art with an injection system which utilizes a single large injection port and which injects intermediate pressurized vapor refrigerant into two different enclosed pockets of a scroll compressor having asymmetric scroll wraps. The single large injection port allows for an increased amount of the vapor to be injected into both of the enclosed spaces without the possibility of the injected vapor migrating to the suction area of the compressor.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.